A 3D display (i.e., stereoscopic image display device) refers to the whole system that enables a user to feel a virtual three-dimensional effect by flat display hardware using binocular disparity generated when a human's eyes are away from each other by about 65 mm in a horizontal direction, among various factors allowing the user to feel the three-dimensional effect. In other words, although a human's eyes view the same object, they see slightly different images (more correctly, horizontal spatial information is slightly divided) due to the binocular disparity. When the two images are delivered to the brain through the retina, the brain precisely unites the two images to allow the user to feel a three-dimensional effect. Based on this, a 2D display device is designed to simultaneously display two left and right images and deliver them to the respective eyes to create a virtual three-dimensional effect, which is called a stereoscopic image display device.
In order to display images of two channels on a single screen in the stereoscopic image display device, in most cases, a channel is output at a time, while changing the lines in one of horizontal or vertical direction on the single screen. When images of two channels are simultaneously output from the single display device, in case of a glass-free scheme, the right image is delivered to the right eye as it is while the left image is delivered only to the left eye, in terms of the hardware structure.
As a representative glass-free method, there has been known a lenticular lens scheme in which a lenticular lens plate on which cylindrical lenses are vertically arranged is installed in front of a display panel. Such a glass-free stereoscopic image display device has been mainly developed in the field of large-scale display devices such as TVs.